/*
** $Id: loslib.c $
** Standard Operating System library
** See Copyright Notice in lua.h
*/

#define loslib_c
#define LUA_LIB

#include "lprefix.h"

#include <errno.h>
#include <locale.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

/*
** {==================================================================
** List of valid conversion specifiers for the 'strftime' function;
** options are grouped by length; group of length 2 start with '||'.
** ===================================================================
*/
#if !defined(LUA_STRFTIMEOPTIONS) /* { */

/* options for ANSI C 89 (only 1-char options) */
#define L_STRFTIMEC89 "aAbBcdHIjmMpSUwWxXyYZ%"

/* options for ISO C 99 and POSIX */
#define L_STRFTIMEC99 "aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%" \
                      "||"                                    \
                      "EcECExEXEyEY"                          \
                      "OdOeOHOIOmOMOSOuOUOVOwOWOy" /* two-char options */

/* options for Windows */
#define L_STRFTIMEWIN "aAbBcdHIjmMpSUwWxXyYzZ%" \
                      "||"                      \
                      "#c#x#d#H#I#j#m#M#S#U#w#W#y#Y" /* two-char options */

#if defined(LUA_USE_WINDOWS)
#define LUA_STRFTIMEOPTIONS L_STRFTIMEWIN
#elif defined(LUA_USE_C89)
#define LUA_STRFTIMEOPTIONS L_STRFTIMEC89
#else /* C99 specification */
#define LUA_STRFTIMEOPTIONS L_STRFTIMEC99
#endif

#endif /* } */
/* }================================================================== */

/*
** {==================================================================
** Configuration for time-related stuff
** ===================================================================
*/

/*
** type to represent time_t in Lua
*/
#if !defined(LUA_NUMTIME) /* { */

#define l_timet           lua_Integer
#define l_pushtime(L, t)  lua_pushinteger(L, (lua_Integer)(t))
#define l_gettime(L, arg) luaL_checkinteger(L, arg)

#else /* }{ */

#define l_timet           lua_Number
#define l_pushtime(L, t)  lua_pushnumber(L, (lua_Number)(t))
#define l_gettime(L, arg) luaL_checknumber(L, arg)

#endif /* } */

#if !defined(l_gmtime) /* { */
/*
** By default, Lua uses gmtime/localtime, except when POSIX is available,
** where it uses gmtime_r/localtime_r
*/

#if defined(LUA_USE_POSIX) /* { */

#define l_gmtime(t, r)    gmtime_r(t, r)
#define l_localtime(t, r) localtime_r(t, r)

#else /* }{ */

/* ISO C definitions */
#define l_gmtime(t, r)    ((void)(r)->tm_sec, luaport_gmtime(t))
#define l_localtime(t, r) ((void)(r)->tm_sec, luaport_localtime(t))

#endif /* } */

#endif /* } */

/* }================================================================== */

/*
** {==================================================================
** Configuration for 'tmpnam':
** By default, Lua uses tmpnam except when POSIX is available, where
** it uses mkstemp.
** ===================================================================
*/
#if !defined(lua_tmpnam) /* { */

#if defined(LUA_USE_POSIX) /* { */

#include <unistd.h>

#define LUA_TMPNAMBUFSIZE 32

#if !defined(LUA_TMPNAMTEMPLATE)
#define LUA_TMPNAMTEMPLATE "/tmp/lua_XXXXXX"
#endif

#define lua_tmpnam(b, e)                       \
    {                                          \
        luaport_strcpy(b, LUA_TMPNAMTEMPLATE); \
        e = mkstemp(b);                        \
        if (e != -1)                           \
            close(e);                          \
        e = (e == -1);                         \
    }

#else /* }{ */

/* ISO C definitions */
#define LUA_TMPNAMBUFSIZE L_tmpnam
#define lua_tmpnam(b, e)                 \
    {                                    \
        e = (luaport_tmpnam(b) == NULL); \
    }

#endif /* } */

#endif /* } */
/* }================================================================== */

static int os_execute(lua_State *L)
{
    const char *cmd = luaL_optstring(L, 1, NULL);
    int stat;
    luaport_errno = 0;
    stat = luaport_system(cmd);
    if (cmd != NULL)
        return luaL_execresult(L, stat);
    else {
        lua_pushboolean(L, stat); /* true if there is a shell */
        return 1;
    }
}

static int os_remove(lua_State *L)
{
    const char *filename = luaL_checkstring(L, 1);
    return luaL_fileresult(L, luaport_remove(filename) == 0, filename);
}

static int os_rename(lua_State *L)
{
    const char *fromname = luaL_checkstring(L, 1);
    const char *toname = luaL_checkstring(L, 2);
    return luaL_fileresult(L, luaport_rename(fromname, toname) == 0, NULL);
}

static int os_tmpname(lua_State *L)
{
    char buff[LUA_TMPNAMBUFSIZE];
    int err;
    lua_tmpnam(buff, err);
    if (l_unlikely(err))
        return luaL_error(L, "unable to generate a unique filename");
    lua_pushstring(L, buff);
    return 1;
}

static int os_getenv(lua_State *L)
{
    lua_pushstring(L, luaport_getenv(luaL_checkstring(L, 1))); /* if NULL push nil */
    return 1;
}

static int os_clock(lua_State *L)
{
    lua_pushnumber(L, ((lua_Number)luaport_clock()) / (lua_Number)CLOCKS_PER_SEC);
    return 1;
}

/*
** {======================================================
** Time/Date operations
** { year=%Y, month=%m, day=%d, hour=%H, min=%M, sec=%S,
**   wday=%w+1, yday=%j, isdst=? }
** =======================================================
*/

/*
** About the overflow check: an overflow cannot occur when time
** is represented by a lua_Integer, because either lua_Integer is
** large enough to represent all int fields or it is not large enough
** to represent a time that cause a field to overflow.  However, if
** times are represented as doubles and lua_Integer is int, then the
** time 0x1.e1853b0d184f6p+55 would cause an overflow when adding 1900
** to compute the year.
*/
static void setfield(lua_State *L, const char *key, int value, int delta)
{
#if (defined(LUA_NUMTIME) && LUA_MAXINTEGER <= INT_MAX)
    if (l_unlikely(value > LUA_MAXINTEGER - delta))
        luaL_error(L, "field '%s' is out-of-bound", key);
#endif
    lua_pushinteger(L, (lua_Integer)value + delta);
    lua_setfield(L, -2, key);
}

static void setboolfield(lua_State *L, const char *key, int value)
{
    if (value < 0) /* undefined? */
        return;    /* does not set field */
    lua_pushboolean(L, value);
    lua_setfield(L, -2, key);
}

/*
** Set all fields from structure 'tm' in the table on top of the stack
*/
static void setallfields(lua_State *L, struct tm *stm)
{
    setfield(L, "year", stm->tm_year, 1900);
    setfield(L, "month", stm->tm_mon, 1);
    setfield(L, "day", stm->tm_mday, 0);
    setfield(L, "hour", stm->tm_hour, 0);
    setfield(L, "min", stm->tm_min, 0);
    setfield(L, "sec", stm->tm_sec, 0);
    setfield(L, "yday", stm->tm_yday, 1);
    setfield(L, "wday", stm->tm_wday, 1);
    setboolfield(L, "isdst", stm->tm_isdst);
}

static int getboolfield(lua_State *L, const char *key)
{
    int res;
    res = (lua_getfield(L, -1, key) == LUA_TNIL) ? -1 : lua_toboolean(L, -1);
    lua_pop(L, 1);
    return res;
}

static int getfield(lua_State *L, const char *key, int d, int delta)
{
    int isnum;
    int t = lua_getfield(L, -1, key); /* get field and its type */
    lua_Integer res = lua_tointegerx(L, -1, &isnum);
    if (!isnum) {                      /* field is not an integer? */
        if (l_unlikely(t != LUA_TNIL)) /* some other value? */
            return luaL_error(L, "field '%s' is not an integer", key);
        else if (l_unlikely(d < 0)) /* absent field; no default? */
            return luaL_error(L, "field '%s' missing in date table", key);
        res = d;
    } else {
        /* unsigned avoids overflow when lua_Integer has 32 bits */
        if (!(res >= 0 ? (lua_Unsigned)res <= (lua_Unsigned)INT_MAX + delta : (lua_Integer)INT_MIN + delta <= res))
            return luaL_error(L, "field '%s' is out-of-bound", key);
        res -= delta;
    }
    lua_pop(L, 1);
    return (int)res;
}

static const char *checkoption(lua_State *L, const char *conv,
                               ptrdiff_t convlen, char *buff)
{
    const char *option = LUA_STRFTIMEOPTIONS;
    int oplen = 1; /* length of options being checked */
    for (; *option != '\0' && oplen <= convlen; option += oplen) {
        if (*option == '|')                                  /* next block? */
            oplen++;                                         /* will check options with next length (+1) */
        else if (luaport_memcmp(conv, option, oplen) == 0) { /* match? */
            luaport_memcpy(buff, conv, oplen);               /* copy valid option to buffer */
            buff[oplen] = '\0';
            return conv + oplen; /* return next item */
        }
    }
    luaL_argerror(L, 1,
                  lua_pushfstring(L, "invalid conversion specifier '%%%s'", conv));
    return conv; /* to avoid warnings */
}

static luaport_time_t l_checktime(lua_State *L, int arg)
{
    l_timet t = l_gettime(L, arg);
    luaL_argcheck(L, (luaport_time_t)t == t, arg, "time out-of-bounds");
    return (luaport_time_t)t;
}

/* maximum size for an individual 'strftime' item */
#define SIZETIMEFMT 250

static int os_date(lua_State *L)
{
    size_t slen;
    const char *s = luaL_optlstring(L, 1, "%c", &slen);
    luaport_time_t t = luaL_opt(L, l_checktime, 2, luaport_time(NULL));
    const char *se = s + slen; /* 's' end */
    struct tm tmr, *stm;
    if (*s == '!') { /* UTC? */
        stm = l_gmtime(&t, &tmr);
        s++; /* skip '!' */
    } else
        stm = l_localtime(&t, &tmr);
    if (stm == NULL) /* invalid date? */
        return luaL_error(L,
                          "date result cannot be represented in this installation");
    if (luaport_strcmp(s, "*t") == 0) {
        lua_createtable(L, 0, 9); /* 9 = number of fields */
        setallfields(L, stm);
    } else {
        char cc[4]; /* buffer for individual conversion specifiers */
        luaL_Buffer b;
        cc[0] = '%';
        luaL_buffinit(L, &b);
        while (s < se) {
            if (*s != '%') /* not a conversion specifier? */
                luaL_addchar(&b, *s++);
            else {
                size_t reslen;
                char *buff = luaL_prepbuffsize(&b, SIZETIMEFMT);
                s++;                                   /* skip '%' */
                s = checkoption(L, s, se - s, cc + 1); /* copy specifier to 'cc' */
                reslen = luaport_strftime(buff, SIZETIMEFMT, cc, stm);
                luaL_addsize(&b, reslen);
            }
        }
        luaL_pushresult(&b);
    }
    return 1;
}

static int os_time(lua_State *L)
{
    luaport_time_t t;
    if (lua_isnoneornil(L, 1))  /* called without args? */
        t = luaport_time(NULL); /* get current time */
    else {
        struct tm ts;
        luaL_checktype(L, 1, LUA_TTABLE);
        lua_settop(L, 1); /* make sure table is at the top */
        ts.tm_year = getfield(L, "year", -1, 1900);
        ts.tm_mon = getfield(L, "month", -1, 1);
        ts.tm_mday = getfield(L, "day", -1, 0);
        ts.tm_hour = getfield(L, "hour", 12, 0);
        ts.tm_min = getfield(L, "min", 0, 0);
        ts.tm_sec = getfield(L, "sec", 0, 0);
        ts.tm_isdst = getboolfield(L, "isdst");
        t = luaport_mktime(&ts);
        setallfields(L, &ts); /* update fields with normalized values */
    }

    // if (t != (luaport_time_t)(l_timet)t || t == (luaport_time_t)(-1))
    //   return luaL_error(L,
    //                 "time result cannot be represented in this installation");
    l_pushtime(L, t);
    return 1;
}

static int os_difftime(lua_State *L)
{
    luaport_time_t t1 = l_checktime(L, 1);
    luaport_time_t t2 = l_checktime(L, 2);
    lua_pushnumber(L, (lua_Number)luaport_difftime(t1, t2));
    return 1;
}

/* }====================================================== */

static int os_setlocale(lua_State *L)
{
    static const int cat[] = { LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY,
                               LC_NUMERIC, LC_TIME };
    static const char *const catnames[] = { "all", "collate", "ctype", "monetary",
                                            "numeric", "time", NULL };
    const char *l = luaL_optstring(L, 1, NULL);
    int op = luaL_checkoption(L, 2, "all", catnames);
    lua_pushstring(L, luaport_setlocale(cat[op], l));
    return 1;
}

static int os_exit(lua_State *L)
{
    int status;
    if (lua_isboolean(L, 1))
        status = (lua_toboolean(L, 1) ? EXIT_SUCCESS : EXIT_FAILURE);
    else
        status = (int)luaL_optinteger(L, 1, EXIT_SUCCESS);
    if (lua_toboolean(L, 2))
        lua_close(L);
    if (L)
        luaport_exit(status); /* 'if' to avoid warnings for unreachable 'return' */
    return 0;
}

static const luaL_Reg syslib[] = {
    { "clock", os_clock },
    { "date", os_date },
    { "difftime", os_difftime },
    { "execute", os_execute },
    { "exit", os_exit },
    { "getenv", os_getenv },
    { "remove", os_remove },
    { "rename", os_rename },
    { "setlocale", os_setlocale },
    { "time", os_time },
    { "tmpname", os_tmpname },
    { NULL, NULL }
};

/* }====================================================== */

LUAMOD_API int luaopen_os(lua_State *L)
{
    luaL_newlib(L, syslib);
    return 1;
}
